Delayed Monocular Blindness after Coil Embolization of Large Paraclinoid Aneurysm

Treatment of paraclinoid aneurysms weather by surgery, or endovascular embolization has a risk of visual loss due to optic neuropathy, or diplopia due to cranial nerve palsies. Visual complications occur immediately after the clipping, whereas they can occur variable time after endovascular coiling. Recently, endovascular coiling for paraclinoid aneurysm is regarded as a safe and feasible treatment. But it still has risks of acute thromboembolic complication, or cranial nerve palsies. A 45-year-old woman was referred from local hospital to our hospital due to ruptured large ICA dorsal wall aneurysm. A total of 12 coils (195 cm) were used for obliteration of aneurysm. Postoperative diffusion weighted image showed no abnormal signal intensity lesion and magnetic resonance angiography demonstrated no sign of vasospasm, or vessel narrowing. But, she complained visual problem 23 days after coil embolization. Ophthalmologist confirmed the left optic disc atrophy on fundoscopy. Although steroid was started, but monocular blindness did not recover completely. The endovascular embolization of paraclinoid aneurysm, especially projecting superiorly with large irregular shape, has the risk of progressive visual loss because of the proximity to optic nerve.